1. Field of the Invention
The present invention relates to an art concerning an electromagnetic actuator that generates axial electromagnetic driving force between an inner axial member and an outer tubular member and relates to the electromagnetic actuator and an active vibration-damping device using the same.
2. Description of the Related Art
Generally, for an active vibration damper or vibration-damping device, which is referred as an active type, the electromagnetic actuator is used in order to obtain oscillation force. The electromagnetic actuator, as shown in Japanese Patent No. JP-B-4643602 for example, has a structure wherein both axial side parts of an inner axial member are elastically supported in relation to an outer tubular member by elastic members and the inner axial member is assembled to be movable relative to the outer tubular member in the axial direction. The electromagnetic force exerted between a stator and a mover acts on the inner axial member and the outer tubular member, thereby providing axial oscillation force.
In the electromagnetic actuator disclosed in JP-B-4643602 mentioned above, the stator is constituted by including a coil member, while the mover is constituted by including a permanent magnet. Through energization in relation to the coil member, the electromagnetic force is generated between the stator and the mover. Therefore, the electromagnetic actuator disclosed in JP-B-4643602 includes a power feed terminal for supplying the coil member with electricity, and an annular member formed of a synthetic resin including the power feed terminal is housed within the outer tubular member.
Regarding the electromagnetic actuator, the internal space that stores a coil etc. is closed tight considering dust and water proof properties in many cases. In the electromagnetic actuator disclosed in JP-B-4643602 mentioned above, the outer peripheral end of the annular member is clamped by the outer tubular member and a bracket fitting from above and below, thereby keeping sealing of the internal space and fixing the annular member to the outer tubular member.
However, since a bobbin supporting the coil is directly fixed to the annular member, vibration of the stator relative to the mover readily travels to the outer peripheral end at which the annular member is supported. Especially, the annular member is formed of the insulative synthetic resin, which may be worn out or damaged. This might deteriorate fixation force for the annular member or affect adversely on vibration transmission from the target of vibration-damping to the housing via the annular member.